Field of the Present Disclosure
Embodiment of the present disclosure relates to a solar cell device.
Discussion of the Related Art
A method for manufacturing a solar cell device for electric generation using a solar energy may be as follows: first, a substrate is prepared, on which a rear electrode layer is formed. Then, the electrode layer is patterned using a laser to form a number of rear sub-electrodes.
Thereafter, on the rear sub-electrodes, a light absorption layer, a buffer layer, and a high resistance buffer layer are formed in this order. In order to form the light absorption layer, two approaches has been widely employed: in a first one, by evaporating copper, indium, gallium, and selenium at the same time or individually, a copper-indium-gallium-selenide (Cu(In,Ga) Se2; CIGS) based light absorption layer is formed; and in a second one, a metal precursor layer is formed, and, thereafter, a selenization process is conducted to the precursor layer to form the light absorption layer. The light absorption layer has an energy band gap of about 1 eV to 1.8 eV.
Next, on the light absorption layer, a buffer layer including a cadmium sulfide (CdS) is formed using a sputtering process. The buffer layer has an energy band gap of about 2.2 eV to 2.4 eV. Then, on the buffer layer, a high resistance buffer layer including a zinc oxide (ZnO) is formed using a sputtering process. The high resistance buffer layer has an energy band gap of about 3.1 eV to 3.3 eV.
After this, groove patterns are formed in a stack of the light absorption layer, the buffer layer and the high resistance buffer layer.
Next, on the high resistance buffer layer, a transparent conductive material is disposed so as to fill the groove patterns. In this way, on the high resistance buffer layer, a transparent electrode layer is formed, and, at the same time, the conductive material filling the groove patterns serves as connection lines respectively. The transparent electrode layer and connection line may be made of, for example, a zinc oxide doped with aluminum. The transparent electrode layer has an energy band gap of about 3.1 eV to 3.3 eV.
Then, on the transparent electrode layer, further groove patterns are formed to form a number of solar cells. Each of the transparent electrodes and the high resistance buffers may correspond to each of the solar cells. The transparent electrodes and the high resistance buffers may be arranged in stripes or matrix form.
The transparent electrodes and the rear sub-electrodes are misaligned with each other. Thus, the transparent electrodes and the rear sub-electrodes may be electrically coupled to each other via the connection lines respectively. In this way, the number of the solar cells may be electrically coupled to each other in a series.
The light absorption layer is formed the rear electrode layer. Specifically, the light absorption layer is formed on the patterned rear electrode layer.
However, after deposition of the light absorption layer, due to a poor bonding force between the light absorption layer and rear electrode layer, and/or the light absorption layer and support substrate in the patterned regions of the rear electrode layer, the light absorption layer may be peeled off from the rear electrode layer and support substrate. This may lead to an increase in an overall electrical resistance of the solar cells, and, thus, deterioration in an overall generation efficiency of the solar cells.
Therefore, there is a need for a solar cell structure with prevention of the light absorption layer from being peeled off.